Roberts is conservative, has only been on the High Court bench
since 2005 and is only 55. So leaving the Supreme Court to allow
Barack Obama to nominate the next Chief Justice and swing the
court back (if you include Kennedy) to a liberal majority would
be basically unheard of.

We'll certainly keep an eye on this one.

Radar's story is
here, but they don't have a lot of detail, and it doesn't
cite a source other than noting it has "learned exclusively."